Method of manufacturing a gas-discharge display panel

ABSTRACT

1. IN THE METHOD OF MANUFACTURING A GAS-DISCHARGE DISPLAY PANEL COMPRISING AT LEAST ONE BOTTOM PLATE AND ONE TOP PLATE OF INSULATING, TRANSPARENT MATERIAL, THE BOTTOM AND TOP PLATES BEING PROVIDED WITH STRIP-SHAPED RELATIVELY INSULATED CONDUCTORS, PARTS OF THE SURFACES OF WHICH ARE IN CONTACT WITH A GAS ATMOSPHER IN CAVITIES BETWEEN THE CONDUCTORS, THE STEPS OF EMBEDDING A COMBSHAPED CONDUCTOR IN AN INSULATING PLATE WITH THE TINES OF THE COMB-SHAPED CONDUCTOR EXTENDING UP TO THE SURFACE OF THE PLATE, AND THEREAFTER CHEMICALLY ETCHING THE TINES TO FORM CAVITIES IN THE INSULATING PLATE.

Oct. 22, 1974 J VAN ESDONK ET AL 3,843,427

METHOD OF MANUFACTURING A GASDISCHARGE DISPLAY PANEL 3 Sheets-Sheot 1 Filed March 1, 1971 Fig.1

AGEN-T' METHOD OF MANUFACTURING A GAS-DISCHARGE DISPLAY PANEL Filed March 1, 1971 Oct. 22, 1974 VAN ESDQNK ET AL 3 Sheets-Sheet 3 INVENTORS \JOHANNES VAN ESDONK y WILHELMUS J. VANDER LAAR AGENT Oct. 22, 1974 VAN ESDONK ET AL 3,843,427

METHOD OF UANUFACTURING A GAS-DISCHARGE DISPLAY PANEL 3 Sheets-Sheet 5 Filed March 1, 1971 Fig.4

AGENT 3,843,427 METHOD OF MANUFACTURING A GAS- DISCHARGE DISPLAY PANEL Johannes van Esdonk, Jacobus Hubertus Jacobs, Johannes Petrus Hornman, and Wilhelmus Johannes van de Laar, Emmasingel, Eindhoven, Netherlands, assignorsto U.S.

Philips Corporation, New York, N.Y.

' Filed Mar. 1, 1971, Ser. No. 119,487 Claims priority, application Netherlands, Mar. 21, 1970,

7004088 Int. Cl. C23f 17/00; Hk 3/06 U.S. Cl. 156-3 4 Claims ABSTRACT OF THE DISCLOSURE Method of manufacturing a gas discharge panel in which the discharge cavities are formed by etching away tines of comb-shaped conductors embedded in the bottom and/or top plates.

The invention relates to a method of manufacturing a gas-discharge display panel comprising at least one bottom plate and one top plate of insulating, transparent materials, the bottom and/or top plates being provided with a plurality of strip-shaped, relatively insulated conductors, parts of the surfaces of which are in contact with a gas atmosphere contained in cavities between the conductors. l

It is not easy to provide cavities between the conductors of the bottom and top plates. In general, a perforated intermediate plate is arranged between the bottom and top plates, the openings of which are located at one end opposite a conductor of the bottom plate and at the other end opposite a conductor of the top plate.

In the method according to the invention at least part of the cavity is formed by embedding comb-shaped conductors in an insulating plate, the tines of the combshaped conductors extending to a surface of the plate, after which the tines are chemically etched away at least partly so that cavities are formed in the insulating plate.

Since the combs can be manufactured mechanically with great accuracy, identical plates with electrodes and cavities accurately distributed along the surface are thus obtained in a comparatively simple manner. Such plates can be joined with superimposition of the cavities so that two cavities together form one discharge cavity between two electrodes.

In order to connect all cavities with a pump channel and a pump tubing, the surfaces of the bottom and top plates may be arranged at a small distance from each other so that all cavities communicate with each other. This distance has to be small, if possible smaller than the free length of travel of the electrons in the gas contained in the cavities in order to avoid a jump of a discharge from one cavity to the adjacent cavities.

In order to avoid sagging of plates of large size supporting ridges may be provided on the surface of one of the plates. These ridges are preferably at right angles to the pump channel, in which case the ridges need not be interrupted. Instead of ridges local, for example, punctiform elevation may be provided on one of the plate surfaces, or alternatively a plurality of balls or grains, preferably of insulating material may be clamped between the plates or be stuck to one of the plate surfaces or to both of them or they may be sintered thereto.

The invention will be described more fully with reference to the accompanying drawing, in which:

FIG. 1 is a perspective, partial sectional view of a plate with embedded conductors, l

FIGS. 2 and 3 show similar sectional views of two embodiments of gas-discharge panels manufactured by the method embodying the invention, and I "United States Patent 0 FIG. 4 is a similar sectional view of a gas-discharge panel for the display of colour pictures.

Referring now to FIG. 1, reference numeral 1 designates a plate of insulating material such as glass, ceramic or an appropriate synthetic resin. In this plate 1 combshaped conductors 3 are embedded, only one of which is shown. The tines 7 of the comb extend just to the surface of the plate 1. The plate 1 is provided in this case with ridges 11, one of which is shown. The height of the ridges 11 is about 50 to /;i, which is in certain cases smaller than the free length of the path of the electrons in the gas of a discharge panel. The conductor 3 with the tines 7 can be pressed into the soft, insulating material of the plate 1 or the insulating material can be cast between the tines of conductor 3 arranged in a jig or it may be inserted in the form of a powder and melted.

Then the ends of the conductor 3 are covered bya protective layer and the plate 1 is introduced into a suitable etching solution so that the tines 7 are dissolved. The tines 7 are preferably dissolved until their top surfaces are level with the interface of the conductors. Thus a top plate 2 or a bottom plate 1 with cavities 10 is obtained.

As is indicated in FIG. 2 the top plate 2 is put down on a bottom plate 1 so that the conductors 4 of the top plate cross the conductors 3 of the bottom plate 1 in this case at right angles. Corresponding cavities 10 of the bottom and top plates together form a discharge cavity between the conductors 3 and 4, whose parts previously formed by the tines 7 now serve as electrode faces 8 and 9 respectively.

The bottom plate 1 is provided with a pump channel 5 which communicates with a pump tubing 6. Since the surfaces of the bottom and top plates are arranged at a small distance from each other, because the bottom plate 1 is provided with a fillet 18, all cavities communicate with each other and with the channel 5 so that they can be exhausted and filled with a suitable gas through the pump tubing 6. In order to avoid sagging of the plates due to the pressure of the open air, the bottom plate is provided with a plurality of ridges 11, which are at right angles to the pump channel 5. The ridges 11 have the same height as the fillet 18.

The plates 1 and 2 are secured to each other in a vacuum-tight manner at the periphery by means of a suitable sealing means 12, for example, cement, glaze or a synthetic resin.

The conductors in the top plate 2 need not be etched away, but their electrode faces 9 may be level with the surface of the plate 12. Instead of tined conductors flat, strip-shaped conductors may be employed, one side of which is located in the plate surface or conductive layers 13 as shown in FIG. 3 may be employed. Then the discharge cavities have a height which is equal to the height of the ridges 11 and to the depth to which the tines of the conductors 3 are etched away. The cavities should have a given minimum depth, which exceeds the free length of the path of the electrons of the gas in. the cavities. If fluorescent material is applied to the sidewalls of the cavities, it is advantageous with regard to the light output to increase the height of the cavities. A great height of the cavities requires, however, the use of long tines 7, which have to be etched away completely so that considerable loss of material is involved. A suitable compromise is obtained with cavities having a height of about 5 mms. and transverse dimensions of about 1 to 2 ms. in accordance with the size of the panel.

In a gas-discharge panel for the display of colour pictures, the phosphors are applied to the inner faces of the cavities. Owing to the lower light output of these prosphors the cavities should have a greater height than in the case of monochrome panels. As is shown in FIG. 4, it is that the plate is deformed. If the conductors 16 themselves are also strongly heated, they may be pressed into the plate 1 without deformation of the cavities. In the panel shown in FIG. 4 a perforated plate 14 is sandwiched between the bottom plate 1 and the top plate 2, ,the, thickness of said plate being about mms. The colour phosphors 20 are applied to the inner walls of the holes 15,. that is to say alternately red, green and blue in different holes 15.

The top plate 2 of FIG. 4 is also provided with cavities ,for med by etching away tines of comb-shaped conductors. The same remark as made :with respect to the top plate of FIGS. 2 and 3 applies in this case. In order to permit of exhausting and fillingthe cavities with a suit able gas, the bottom. plate 1 is provided also in this case with an elevated fillet 18. Since the use of ridges gives ;rise to difficultiesrin this case in connection with the presence of the auxiliary anodes 16, a plurality of punctiform' elevations 17 are provided for avoiding sagging of the plates 1, 2 and 14. The elevations may be formed by glass grains sintered to the surface of the plate 1 or 14. The correct height is obtained by using grains of too large thickness and by flattening them partly by a fiat plate pressed on the fillet 18.

As an alternative in the embodiments of FIG. 4, when straight, strip-shaped conductors 4 without tines are used,

7 it is possible to etch away the portions of the conductors 4 located within the fillet 18 throughout the length to an extent such that channels are formed which connect the cavities with openings 19 opening out in the channel 5.

Although only three embodiments are described herein, other combinations of comb-shaped conductors, stripshaped, smooth conductorsor conductive laye rs, perforated Pla an ns -Qr v ns Mai ema may obviously be employed within the scope of the invention. For example, a thin perforated plate may be sandwiched between the cathodes 3 and the auxiliary anodes 16-. Y

What is claimed'is:

,1. In the method of manufacturing agas-discharge displayf panel comprising at least one bottom plate and one top "plate" of insulating, transparentmaterial, the bottom and top plates being provided 'with strip shaped relatively insulated conductors, parts of' thesurfaces of which are in contact with a gasil atmosphre in cavities between the conductors, thesteps of embedding a'combshaped conductor, in an insulating plate with the tines of 'the comb-shaped conductor extendingupnto ,the surface of the plate, and thereafter chemically etching the tines to form cavitiesv in the insulating plate.

2. A method as "claimed in claims "which the comb-shaped conductor with-the comb-shapedl'conductor is pressed into a plate of soft insulating mate-rial.

3. A method as claimed in Claim 1 in which an'insulating material is cast between the tines of the comb-shaped conductor.

4. A method as claimed in clairnvii in which powdered insulating material is inserted between the tines and .melted. i I 1 References Cited UNITED STATES PATENTS e f 7 3,611,061 7/1971 Sergerson 29-589 3,501,833 3/1970 Spiegler 29-=-627 J. STEINBERG, Primary Examiner U.S. C1. X.R. 

1. IN THE METHOD OF MANUFACTURING A GAS-DISCHARGE DISPLAY PANEL COMPRISING AT LEAST ONE BOTTOM PLATE AND ONE TOP PLATE OF INSULATING, TRANSPARENT MATERIAL, THE BOTTOM AND TOP PLATES BEING PROVIDED WITH STRIP-SHAPED RELATIVELY INSULATED CONDUCTORS, PARTS OF THE SURFACES OF WHICH ARE IN CONTACT WITH A GAS ATMOSPHER IN CAVITIES BETWEEN THE CONDUCTORS, THE STEPS OF EMBEDDING A COMBSHAPED CONDUCTOR IN AN INSULATING PLATE WITH THE TINES OF THE COMB-SHAPED CONDUCTOR EXTENDING UP TO THE SURFACE OF THE PLATE, AND THEREAFTER CHEMICALLY ETCHING THE TINES TO FORM CAVITIES IN THE INSULATING PLATE. 